Yingkun Li

• Doctor of Engineering
• Professor (Associate) at Nanjing University of Science and Technology

In this paper, numerical investigation of ignition transient in a dual pulse solid rocket motor has been conducted. An in-house code has been developed in order to solve multi-physics governing equations, including unsteady compressible flow, heat conduction and structural dynamic. The simplified numerical models for solid propellant ignition and c...

The flow characteristics of shock train in the isolator play an important role in the overall performance of scramjet. The current study proposes a new concept shock train control strategy based on the aeroelastic effect of the flexible panel. An in-house developed code was used to solve the compressible Navier-Stokes equations and the geometric no...

Aluminum (Al) is usually added to solid propellants to improve the combustion performance, however the condensed combustion products (CCPs) especially the large agglomerates generated from aluminum combustion can reduce the specific impulse of the engine, and result in two-phase loss, residue accumulation and throat liner ablation. Al and ammonium...

This paper presents a computational fluid dynamics study of morphology and structure dynamics of the flow over a supersonic secant-ogive cylinder boat tail projectile under heavy rain. The discrete phase model is employed to approximate the process of droplet–particle collision with the projectile wall and the formation of a liquid film. The simula...

In order to study the combustion process and aluminum agglomeration characteristics of NEPE propellant，the combustion process of NEPE propellant was recorded by the optical imaging method combined with a high-speed camera and a long distance microscope， the combustion wave flame was recorded by an infrared thermal imager， and the condensed combusti...

Aluminum (Al) particles are commonly added to energetic materials including propellants, explosives and pyrotechnics to increase the overall energy density of the composite, but aluminum agglomeration on the combustion surface may lower the combustion efficiency of propellants, resulting in a loss in two-phase flow. Therefore, it is necessary to un...

In this paper, a self-developed solver is used to numerically simulate the isolator section under complex inlet conditions, and the influence of forced panel vibration on the shock flow field in the isolator under complex inlet conditions is investigated. The results show that the forced vibration of the panel has a certain influence on the shock f...

In order to study the influence of the deformations of the nozzle’s flexible sections on its inner wall’s heat transfer, this research uses the two-dimensional axisymmetric model and the k − ω SST turbulence model to numerically analyze the tail flow field of the flexible-extendible nozzle under multiple working conditions. The flow field and the i...

Aiming at the dynamic behavior of aluminum agglomerates on the burning surface of NEPE propellant, the dynamic combustion process of aluminum agglomerates at the surface and out of the burning surface of aluminum in the NEPE propellant was studied under 1MPa, 2MPa, 3MPa nitrogen environment, and a simplified theoretical model for the burning surfac...

In this work, a new configuration of strut-based scramjet is proposed, and a series of simulations are conducted to investigate its possibility of practical application. The simulation results are verified via the classical DLR ramjet and an experiment conducted on the connected pipe facility. The inlet area ( A in ) and air intake height ( H ) of...

Nitrate ester plasticized polyether (NEPE) propellant is widely used in solid rocket motors, having both good mechanical properties and high specific impulse. However, its ignition and combustion process are complex and need to be better understood. In this study, a high-pressure sealed combustion chamber was constructed, a thermogravimetry-differe...

We investigate the effects of aging and damage on the mechanical behavior of composite modified double-base (CMDB) propellants in uniaxial tension under high-temperature aging. We measure the relaxation modulus curves and stress–strain relationships of CMDB propellants at different accelerated aging times. The results show that aging has a signific...

In this paper, aiming at the problem of heat transfer and ablation prediction of phenolic resin/nitrile rubber in the insulation material in double pulse motor, based on pyrolysis kinetics and thermochemical ablation theory, a variable heat physical property model of nitrile rubber insulation material with temperature and time was established. A si...

High-speed airbreathing engines has been going on for more than a century, since French engineer Reina Lauren first developed the concept of the ramjet. Kelvin-Helmholtz (K-H) instability and compressibility effects on the evolution of supersonic mixing layer growing rate have been widely investigated in experimental and computational ways. The pre...

In the present research, Schardin’s problem is numerically investigated using a FORTRAN based quasi-DNS solver, the numerical results are validated using the experimental result and the shock impinges process is analyzed in detail. During the shock impinges process, we noticed that the periodical vortex shedding phenomena could be observed, thus, t...

In order to understand the ignition and combustion characteristics of NEPE propellants under different pressure conditions and the agglomeration behavior of aluminum particles on the burning surface, the Al/NEPE propellant was tested on a sealed high‐pressure laser ignition platform. Laser ignition experiments show that both ignition delay time and...

Pasty rocket engines have broad application prospects in the aerospace field. To study the internal ballistic characteristics of the pasty propellant rocket engine, the burning surface change model of pasty propellant was built. The calculation program was developed to calculate the pressure evolution in the combustion chamber, and the experiment w...

In this paper, the second pulse ignition transient in a dual pulse solid rocket motor with elastomeric barrier pulse separation device has been conducted numerically. An in-house code has been developed to solve governing equations for unsteady compressible flow, heat conduction and structural dynamic. The solid propellant ignition and burning nume...

Enhancing the combustion efficiency of gas fuel, i.e., hydrogen, in supersonic reacting flows has attracted wide attention around the world, besides, the flame holders are the key components of scramjet engines which even can make the injected fuel and local air mix and burn better in milliseconds. In previous researches, two struts with backward f...

How to effectively reduce aeroheating load and drag is an important issue in the engineering application of the hypersonic vehicles. In this paper, a novel combined aerodisk-spike root oblique jet strategy has been proposed for drag and heat reduction. The Reynolds-averaged Navier Stokes equations are solved based on the finite volume method, and t...

In this paper, the fluid solid coupling in the cold-flow impact process of the soft pulse separation device of dual pulse solid rocket motor is numerically simulated by using ANSYS Workbench software. This paper mainly analyzes the flow characteristics of the flow field near the interlayer, deformation and stress change of interlayer under the cold...

Huge aerodynamic drag and severe aeroheating are the inevitable challenges for hypersonic vehicles, this paper proposes a novel combined spike-aerodome and lateral jet strategy for drag reduction and thermal protection. Meanwhile, the hypersonic flow characteristics and structure thermal response are numerically investigated by an in-house code. Th...

Scramjet is one of the most promising propulsion systems for the new generation supersonic/hypersonic air-breathing flight vehicles. To achieve sufficiently high combustion efficiency and relatively low total pressure loss, developing a new strut is an attractive approach. In this study, we focus on the backward-facing steps and investigate the geo...

This paper presents a numerical investigation of ignition and combustion stabilization of a novel design of a solid-fuel ramjet (SFRJ) motor with and without swirl flow. The proposed design includes two solid fuels, retaining the simple design of the classic SFRJ. Numerical simulations of unsteady, turbulent, reactive, and swirling flow coupled wit...

Hypersonic vehicles have attracted lasting and worldwide attention in recent years. Considerable aerodynamic drag and severe aerothermal loads are major challenges for hypersonic vehicles. A novel combinational aerodisk and lateral jet concept is proposed for drag reduction and thermal protection in hypersonic flows. The flow field characteristics...

In this paper, the influence of swirl intensity on solid fuel regression rate and combustion phenomena in a solid fuel ramjet has been investigated numerically and experimentally. First, an in-house code has been developed to solve axisymmetric Reynolds-averaged Navier–Stokes equations of unsteady turbulent swirling compressible flow field with che...

In order to investigate the characteristics of drag and heat reduction by a combinational lateral jet and spike in supersonic flows, based on the finite volume method the unsteady Reynolds-average Navier-Stokes (RANS) equations was solved by using high resolution upwind scheme AUSMPW+, 3 order MUSCL reconstruction method and k-ω SST turbulence mode...

When flying at supersonic or hypersonic speeds through the air, the drag and severe heating have a great impact on the vehicles, thus the drag reduction and thermal protection studies have attracted worldwide attention. In the current study, the Reynolds-averaged Navier-Stokes (RANS) equations coupled with the shear stress transport (SST) k−ω turbu...

In order to study the second pulse ignition transient of a dual pulse solid rocket motor, a multi-physic solver is developed. The governing equations for unsteady compressible fluid flow are solved with dual time LU-SGS (lower upper symmetric Guass seidel) iterative algorithm by finite volume method. The conjugate heat transfer strategy is employed...

Numerical simulations were performed to study the influence of the inside diameter of the pulse separation device port on the flow features and the local heat transfer characteristics in a dual pulse solid rocket motor. A lower–upper symmetric Gauss–Seidel implicit dual time-stepping method was applied to address the problem of unsteady flow. A hig...

In order to investigate the influence of solid fuel ramjet geometry on regression rate of solid fuel, a 2D axisymmetric turbulent flow and combustion program is developed. The Navier-Stokes governing equations are solved by using MUSCL reconstruction method and AUSMPW+ flux splitting technique, k-w SST turbulence model, 7 species/3 reaction kinetic...

The flow-field characteristics of the supersonic, arc-heated plasma thrusterwere empirically simplified, mathematically modeled, theoretically calculatedby solving the magneto-hydrodynamics governing equations based on the magnetic vector potential, and numerically simulated with software Fluent and the self-defined function, involving a source-ter...

A conjugate heat transfer (CHT) code has been developed for the complex thermal protection structures with non-orthogonal fluid/solid interfaces. Both fluid- and solid- domains employ the integral and conservative form of the Reynolds-Averaged Navier-Stock(RANS) equations, which are discretized by means of the finite volume scheme. To keep the heat...

The effects of the pulse separation device port diameter on heating environment of thermal insulation of the first pulse chamber in a dual pulse motor were simulated. The Reynolds-average Navier-Stokes equations were solved with dual time LU-SGS iterative algorithm, AUSMPW upwind scheme, modified shear-stress-transport (SST) turbulence model which...

To address the conjugate heat transfer problem in complex geometries, a coupling approach based on the local coordinate transformation is developed to evaluate the common wall temperature on non-orthogonal solid–fluid interfaces. The proposed coupling approach is validated and then used to investigate the erosion-induced shape change effects in a c...

In order to study the effects of anode geometry on volt-ampere characteristics and plasma jet characteristics of the arcjet thruster, the arcjet thruster flow characteristics were simulated. Through numerical simulation, the velocity field and temperature field of thruster were calculated, and the volt-ampere characteristics were obtained at differ...

In order to study the effects of two-stage pulse channel configurations on reattachment location and relative convective heat transfer coefficient in combustion chamber of dual pulse motor, the Reynolds-average Navier-Stokes equations were solved with three-order three-step Runge-Kutta iterative algorithm by cell center upwind finite volume method...

In order to accurately simulate the solid rocket motor inner flow field, the Reynolds-average Navier-Stokes equations were solved with three-order three-step Runge-Kutta iterative algorithm by cell center finite volume method, AUSM-PW scheme were implemented for spatial discretization. Also, SST (shear-stress-transport) turbulence model developed b...

A conjugate heat transfer(CHT)code was developed to study the flow structure and heat transfer of a nozzle under different expansion states. Navier-Stokes equations were used to govern both fluid and solid regions, cell-center based finite volume method was adopted to solve the governing equations, and k-ω SST model was used for turbulence closure....

In order to study the influence of the nozzle flow field in dual pulse solid rocket motor with moving plugs, the unsteady Reynolds-average Navier-Stokes equations were solved with dual-time step LU-SGS iterative algorithm by cell center finite volume method, AUSM-PW scheme was implemented for spatial discretization. The process of the plug moving i...